Got my Z running, needs more fuel

[Force Fed]

Actually got it running a month or so ago, just now getting around to posting From what I can tell, it has a complete '81 or '82 2.8 long block (not a 2.8 short block and 240 head as it was supposed to have, but oh well) w/ stock SU's bolted on it. Runs great, as long as the cold start lever is pulled all the way on Needs richer needles, which ones should I get you think? I remember reading that there were only like 2 needles that work good on 2.8's, one of them being a British SU needle. The head has N47, which I believe is a '81 or '82 Maxima head, and therefore probably the whole engine. It does have a 3-2-1 header on it.

BTW this is in my '72 240Z 4-spd.

[MikeW]

Does it still run rough even after getting completely warmed up? I don't think the stock needles would cause a problem with a 2.8.

[sblake01]

The head has N47, which I believe is a '81 or '82 Maxima head, and therefore probably the whole engine.

If it's an 81 or 82 with a N47 head and you believe it's the whole engine from a Maxima then it's an L24E not an L28. That makes sense since I doubt anyone would put that head on a L28. Your problem may be the EFI liners in that head.

[Force Fed]

Yeah even when it warms up it runs rough if the choke/cold start isn't fully on. Pull it on all the way and it'll rev like a banshee, sounds great. What number do I need to look for on the block to see what engine it is? I looked once couldn't find anything I recognized from searching on here. Although I am still a noob on these cars I just bought a new slave and clutch hose on ebay for it, so I should be able to drive it around some soon.

[ekaphoto]

I am far from being an expert, but have you tried to raise your needles a little?

[sblake01]

What number do I need to look for on the block to see what engine it is?

If it's an L24E, it would have 'P30' stamped on the block just ahead of the drivers side motor mount or 'F54' if it's a 80-83 ZX engine or 'N42' if it's a 75-80 engine. Or look on the side of the block just below the 5 and 6 sparkplug. It should have 'L24' or 'L28' as the first three characters before the numbers depending on which it is.

[beandip]

The problem is not liners in the exhaust ports. I am running a F-54 engine out of a '82ZX with a mild cam and the head is milled so I have 9.5 compression. Not that high but higher than stock and I still can run any pump gas with out a problem. I have SUs and I have tried several different needles. From SMs way too rich to the point I was washing the oil off the cylinder walls and getting gasoline in the oil. 58s too lean and a few others. I finally settled in on F-54s as the best all around needle. I thought as you that because now she is running headers and a cam and a 280, I needed more fuel. I live close to sea level and I set the needles exactly as recommended in the manual, flush with the vacuum piston's top. If you are running lean as you describe you need to back out he mixture adjustments on the carbs. Your present carbs will supply all this engine can handle, and more, if tuned properly.

Do a search on how to adjust SU carburetors , here on this web site. Buy a uni-sen to balance the air flow, you are lost with out one or it's equivalent. Gary

[Force Fed]

Thanks guys, I'll try your suggestions. I never even thought about raising the needles a bit, just set them flush. Basically, if the cold start isn't on it'll idle but when you try to rev it it spits back through the carbs, if you ease it up it'll rev up but you can hear it skipping and missing. With the cold start on, it sounds great. SM needles are the British needles right? I'll check out the carb tuning stuff on here.

Beandip, are you running a 2.8? I'm gonna look today for my block numbers.

[bob m]

You might want to check with ztherapy since you are using SUs. I bought new needles from them for a 280 motor.

Bob M

[beandip]

Thanks guys, I'll try your suggestions. I never even thought about raising the needles a bit, just set them flush. Basically, if the cold start isn't on it'll idle but when you try to rev it it spits back through the carbs, if you ease it up it'll rev up but you can hear it skipping and missing. With the cold start on, it sounds great. SM needles are the British needles right? I'll check out the carb tuning stuff on here.

Beandip, are you running a 2.8? I'm gonna look today for my block numbers.

Yes my present engine is a 280ZX . the part numbers for the 54 needles at Nissan are 16354-E8810 And my engine runs strong . all the best , Gary

[Bruce Palmer]

Sounds like it's lean. Have to pull the chokes on to get it to run? That's richening.... Spittiing back through the carbs w/ the chokes off?.... That's a lean indicator. Try lowering both fuel nozzles a half turn and see what happens. If that improves the situation, try another quarter or half.

[Force Fed]

Sounds like it's lean. Have to pull the chokes on to get it to run? That's richening.... Spittiing back through the carbs w/ the chokes off?.... That's a lean indicator. Try lowering both fuel nozzles a half turn and see what happens. If that improves the situation, try another quarter or half.

I know it's lean I doubt if there's enough adjustment in the nozzles, I have to have the choke lever pulled fully on for it to run properly. So, I'd have to have the nozzle adjuster nut screwed damn nearly off to get close. My first order of business is to make sure whether I have a 2.4 or 2.8, as I'm sure that will make a difference in what needles I need.